# 8: Introduction to t-tests

• 8.1: The t-statistic
The z-statistic was a useful way to link the material and ease us into the new way to looking at data, but it isn’t a very common test because it relies on knowing the populations standard deviation, σ, which is rarely going to be the case. Instead, we will estimate that parameter σ using the sample statistic s in the same way that we estimate μ using X. Our new statistic is called t, and for testing one population mean using a single sample (called a 1-sample t -test)
• 8.2: Hypothesis Testing with t
Hypothesis testing with the t-statistic works exactly the same way as z-tests did, following the four-step process of (1) Stating the Hypothesis, (2) Finding the Critical Values, (3) Computing the Test Statistic, and (4) Making the Decision.
• 8.3: Confidence Intervals
• 8.E: Introduction to t-tests (Exercises)